Limb SL, Brown KC, Wood RA, et al. J Allergy Clin Immunol. 2005;116:1213–1219
PURPOSE OF THE STUDY. Asthma is traditionally characterized as reversible airway obstruction. Yet, it is readily apparent that some individuals develop varying degrees of fixed obstruction associated with structural changes in the airway and that such a course is often marked early in life. These investigators sought to study the frequency, severity, and reversibility of pulmonary deficits in adults with a history of previously well-characterized moderate-to-severe childhood allergic asthma.
STUDY POPULATION. Subjects (N = 121) previously enrolled onto a randomized trial of immunotherapy for childhood asthma were recalled. This original group, aged 5 to 12 years at randomization between 1984 and 1994, had physician-diagnosed asthma and required daily medications for at least 1 year before enrollment. The original study evaluations included daily symptom diaries, home visits, allergy skin testing, and methacholine challenges with associated spirometry. The primary outcome variable was daily medication-usage score as a measure of disease severity. No differences between the placebo and active-immunotherapy groups were appreciated over the course of the study; both groups saw decreases in medication use and methacholine sensitivity.
METHODS. With the current study, an attempt was made to contact all 121 original study subjects, now aged 18 to 31 years. Subjects underwent spirometry and allergy skin testing, and interim medical histories were taken. Individuals with postbronchodilator forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), or FEV1/FVC of ≤5th percentile or at least 2 of these parameters at <10th percentile were categorized as abnormal. These subjects were prescribed 1 mg/kg per day prednisone for 1 week before follow-up pulmonary-function testing, physical examination, and a chest radiograph to assess steroid responsiveness of lung deficits.
RESULTS. Of the 84 subjects reevaluated, 40 (48%) had ≥1 abnormal spirometric index (P < .0001). Of these 40 subjects, 28 were reassessed after prednisone, and 21 (75%) did not improve. Adult and childhood spirometric results were positively correlated. Abnormal adult spirometric results were associated with a longer duration of asthma at enrollment in the original trial, increased childhood methacholine sensitivity, and birth prematurity. Childhood immunotherapy status was unrelated to adult lung function.
CONCLUSIONS. Many adults with a history of moderate-to-severe allergic asthma in childhood have irreversible lung-function deficits. Childhood parameters that might identify such individuals at a young age include spirometry, duration of asthma, methacholine sensitivity, and birth prematurity.
REVIEWER COMMENTS. The authors pointed out that their findings mesh with others’ observations of early disease magnitude, including measurable airway obstruction, which serves as a major predictor of continuation of significant disease into adulthood. Should not every child on maintenance asthma-drug therapy have spirometry results documented, if not monitored? Because all subjects in the current study were allergic, allergy itself did not stand out here as a risk factor, although it most definitely was. To date, no drug-therapy intervention convincingly alters this disease entrenchment.
- Copyright © 2007 by the American Academy of Pediatrics